Project Lyra: Sending a spacecraft to 1I/’Oumuamua (former A/2017 U1), the interstellar asteroid

The first definitely interstellar object 1I/‘Oumuamua (previously A/2017 U1) observed in our solar system provides the opportunity to directly study material from an other star system. Can such objects be intercepted? The challenge of reaching the object within a reasonable timeframe is formidable due to its high heliocentric hyperbolic excess velocity of about 26 km/s; much faster than any vehicle yet launched. This paper presents a high-level analysis of potential near-term options for a mission to 1I/‘Oumuamua and potential similar objects. Reaching 1I/‘Oumuamua via a spacecraft launched in a reasonable timeframe of 5-10 years (launch in 2022-2027) requires an Earth departure hyperbolic excess velocity between 33 and 76 km/s for mission durations between 30 and 5 years, respectively. Different mission durations and their velocity requirements are explored with respect to the launch date, assuming direct impulsive transfer to the intercept trajectory. In addition, missions using a powered Jupiter gravity assist combined with a solar Oberth manoeuvre are explored, using solid rocket engines and Parker Solar Probe heat shield technology. For such a mission, a Falcon Heavy-class launcher would be able to launch a spacecraft of dozens of kilograms towards 1I/‘Oumuamua, if launched in 2021. An additional Saturn gravity assist would allow for the launch of a New Horizons-class spacecraft. Further technology options are outlined, ranging from electric propulsion, and more advanced options such as laser electric propulsion, solar and laser sails. To maximize science return, decelerating the spacecraft at ’Oumuamua is highly desirable, compared to the minimal science return from a flyby. Electric and magnetic sails could be used for this purpose. It is concluded that although reaching the object is challenging, there seem to be feasible options based on current and near-term technology.